Sealing method for electric wire connection

ABSTRACT

A method of using a sealing material for an electric wire connection, comprising a tape-form releasable material, viscous sealing pieces comprising a waterproofing compound, each piece having a width narrower than the width of the releasable material and being releasably formed on one surface of the releasable material, and a sheet-form base material having a larger area than the viscous sealing piece such that each end of the base material projects over each edge portion of the viscous sealing piece formed in one body on each viscous sealing piece. The method includes supplying the sealing material from a tape-form releasable material, the sealing material provided thereon at a constant interval covering the electric wire connection, and pressing the sealing material to adhere to the surfaces of the electric wires.

This is a divisional of application Ser. No. 07/701,913 filed May 17,1991, now U.S. Pat. No. 5,246,755.

FIELD OF THE INVENTION

The present invention relates to a sealing material for an electric wireconnected portion, which is used for a sealing treatment of an electricwire connected portion, a sealing method for an electric wire connectedportion, and a method of producing such a sealing material.

BACKGROUND OF THE INVENTION

Hitherto, in the case of a sealing treatment of a small sized electricwire connected portion, in particular, a branched electric wireconnected portion (e.g., a branched portion of a wire harness of anautomobile), it is known that an electric wire connected portion iscovered with a composite sealing material wherein a viscous sealingpiece is formed on one surface of a film with the viscous sealing piecebeing inside and pressing the sealing material by a press, whereby theviscous sealing piece is pressed into the portion to be sealed, such asan inner corner portion between the end of the coated layer on electricwires and a conductor connecting metal fittings as described in U.S.Pat. No. 4,862,535.

In this method, the composite sealing material covering the electricwire connected portion is pressed with a press in a state of coveringthe viscous sealing piece with the film.

However, since the viscous sealing piece of the composite sealingmaterial is packed up in a small unit, the sealing work cannot becontinuously carried out and it is difficult to employ automation forthe sealing work. Also, a sealing piece has an intermediate propertybetween a fluid and an elastic material, but in the above method, theproperty of the viscous sealing piece as a fluid is utilized for thecompression of the viscous sealing piece. That is, a system wherein thefluid is contained in cells of the film and the fluid is pressed byreduction of the volume in the cell by compression is used. Accordingly,it is necessary to press the composite sealing material which covered anelectric wire connected portion by folding the sealing material in astate of closing the end of the film. Thus, the force of pressing isincreased, the pressing operation is complicated, and the sealing pieceis extruded to cause a hindrance for the subsequent work.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a sealing material foran electric wire connected portion which can continuously supply thesealing materials and in the case of sealing an electric wire connectedportion by covering the electric wire connected portion with a compositesealing material wherein a viscous sealing piece is formed on onesurface of a film with the viscous sealing piece being inside andpressing the sealing piece with a press, and is capable of easilyperforming the pressing operation by utilizing the elastic property ofthe viscous piece in the composite sealing material, and also to providea sealing method of an electric wire connected portion by using thesealing material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plane view showing an example of the sealing material ofthe present invention,

FIG. 1B is a sectional view of the sealing material of FIG. 1A cut alongthe line b--b,

FIG. 2 and FIG. 3 each is a plane view showing other example of thesealing material of the present invention,

FIG. 4, FIG. 5, and FIG. 6 each is a sectional view showing each exampleof the sealing material of the present invention releasing eachreleasable material,

FIG. 7 and FIG. 8 each is a plane view showing a press type which isused for pressing a covered material with the sealing material of thepresent invention, and

FIG. 9 is a slant view showing an electric wire connected portion sealedby the sealing method of the present invention.

DETAILED DESCRIPTION ON THE INVENTION

The sealing material for an electric wire connection according to thepresent invention comprises a tape-form releasable material, viscoussealing pieces comprising a waterproofing compound, each piece having awidth narrower than the width of the releasable material and beingreleasably formed on one surface of the releasable material, and asheet-form base material having a larger area than the viscous sealingpiece such that each end of the base material projects over each edgeportion of the viscous sealing piece formed in one body on each viscoussealing piece.

In the sealing material of the present invention, a mark such as aconcaved groove or a convex line for doubling the viscous sealing piecealong an almost center line can be formed or such a mark can be formedby using a viscous material having a different color.

Also, the sheet-form base material which is formed in one body on theviscous sealing piece usually comprises a soft polyvinyl chloride filmor sheet having flexibility and a good insulating property. Thesheet-form base materials may be separately from each other or in acontinuous form, but in the latter case, it is preferred that a cuttingline is formed between each of the base materials such that each basematerial can be separated from other base material.

Another embodiment of the present invention is to provide a sealingmethod for an electric wire connected portion, which comprises coveringthe electric wire connected portion comprising a main wire and branchedwires with the sealing material for electric wire connected portionseparated from the tape-form releasable material with the viscoussealing piece being inside, and pressing the covered material from atleast one side of the direction nearly parallel with the coveredmaterial to adhere the viscous sealing piece to the surfaces of theelectric wires.

Furthermore, in the sealing material for an electric wire connectedportion having the mark for doubling, the electric wire connectedportion is covered with the sealing material separated from thetape-form releasable material using the mark as a basis with the viscoussealing piece being inside, and the viscous sealing piece is adhered tothe surfaces of the electric wires by the same manner as above.

As a pressing means, a press mold can be used, and it is preferred thatmany small projections are dispersedly formed on the surface of thepress mold which contacts with the covered material or many convexstripes are formed on the surface of the press mold.

Also, in the present invention, by extending the inner viscous sealingpiece by compressing in the thickness direction by pressing the coveredmaterial, i.e., the electric wire connected portion covered with thesealing material of the present invention, the viscous sealing piece isstrongly adhered to the connected portion of the electric wires and thesurfaces of the electric wires to provide a sufficient watertightproperty.

Furthermore, in the sealing material of the present invention, theviscous sealing piece exists in the inside of the edges of thesheet-form base material and hence the protrusion of the viscous sealingpiece from the edges of the base material can be prevented when theviscous sealing piece extends by pressing, whereby attaching of theviscous sealing material to hands, the press mold, and/or other articlescan be prevented.

The present invention is further described in more detail by referenceto the accompanying drawings.

As shown in FIG. 1A which is a plane view showing an example of thesealing material of the present invention and FIG. 1B which is asectional view cut at the line b--b in FIG. 1A, viscous sealing pieces 3are formed on one surface of a tape-form releasable material 4 and asheet-form base material 1 is formed in one body on the viscous sealingpiece 3. In addition, as shown in FIG. 1B, an adhesive layer 2 may beformed, if necessary, on the base material 1 at the sealing piece side.

The releasable material 4 shown in FIG. 1A is generally aself-supporting material comprising a paper and a plastic layer coatedthereon, and usually a layer of a resin showing a low adhesive propertyto a viscous material, such as a silicone resin, is formed on thesurface of the plastic layer. The releasable material 4 may, as the casemay be, comprise of a plastic film or sheet having a self-supportingproperty, such as polyester and polyolefin.

There is no particular restriction on the length of the releasablematerial 4, but the releasable material can have a length capable oftemporarily attaching releasably from several to several thousandsinsulating pieces A each comprising a sealing piece 3 and a basematerial 1. If the releasable material having many pieces A attachedtemporarily is wound in a roll form, the keeping space thereof can besmall.

There is no particular restriction on the size of the viscous sealingpiece 3 if the width of the sealing piece 3 is narrower than the widthof the releasable material 4, and the form of the sealing piece 3 is notonly a rectangle as shown in the Figures but also may be, for example, adisk, a trapezoid, etc.

It is fundamentally necessary that one sheet-form base material 1 isindependently formed in one body on each viscous sealing piece 3, but asshown in FIG. 3, the sheet-form base material 1 may comprise asubstantially continuous long base material having each cutting line 5such as a sewing machine seam, etc., between two sealing pieces capableof being separated at the cutting line.

Also, as shown in FIG. 1A, the base materials 1 may be formed in a stateof substantially contacting with each other or as shown in FIG. 2, thebase materials 1 may be formed with a gap shogun by a mark e betweenthem. The width of the base material 1 is preferably narrower than thewidth of the releasable material 4 as shown in FIG. 1A, FIG. 2, and FIG.3, but the width of the base material may be same as or broader than thewidth of the releasable material 4. In any cases, it is desirable thatall the edge portions of the sheet-form base material 1 protrude overthe viscous sealing piece 3.

The viscous sealing piece can comprise a waterproofing compound havingexcellent adhesion to electric wires, insulating property, and waterresistance. The waterproofing compound comprises a synthetic rubberincluding a non-vulcanized butyl rubber and compounding agents such as aplasticizer, a rubber reinforcing agent, a filler, a softening agent,etc. The thickness of the viscous sealing piece is in the range of from0.5 mm to 10 mm and is required to be at least 1/3 of the outsidediameter of electric wires being sealed.

As the sheet-form base material, a soft polyvinyl chloride film or sheetis used as described above, but polyolefins, thermoplastic elastomers,etc., may be used and a material which extends temporarily by pressingof the covered material and can be restored by removing the stress canbe used.

At the contact side of the viscous sealing piece 3 with the releasablematerial 4 (that is, the contact side with the electric wire connectedportion) can be formed a mark at an almost center line in a directionparallel to or perpendicular to the lengthwise direction of thereleasable material 4 from one side of the sealing piece 3 to the otherside. The mark is useful for correctly matching the position of theelectric wire connected portion.

FIG. 4 shows the mark formed by a concaved groove 3, FIG. 5 shows themark formed by two parallel convex lines 32, 32, and FIG. 6 shows themark formed by a viscous material 33 composed of the same material asthe viscous sealing piece 3 but having a different color. However, itwill be understood that other marks can be employed in the presentinvention.

The sealing material for electric wire connection of the presentinvention can be produced continuously and at a low cost by thefollowing two methods.

According to one method, a viscous sealing material is extruded from adie in a tape form, the tape form material is cut in a width narrowerthan the width of a tape-form releasable material travelling at a crossdirection and in front thereof to form each viscous sealing piece, theviscous sealing pieces are attached onto the continuously orintermittently travelling tape-form releasable material with a constantinterval, and before or after attaching the viscous sealing piece, thesheet-form base material is attached in one body onto the sealing piece.

According to another method, a viscous sealing material is extruded froma die in a tape form, the tape-form viscous sealing material is attachedto the surface of a continuous long sheet-form base material havingprojected portions with a constant interval at the opposite surface ofthe base material, the tape-form sealing material is cut at theprojected portions together with the sheet-form base material, and thecut pieces are attached onto a travelling tape-form releasable material(having a width broader than the width of the viscous sealing piece ofthe cut piece) at a constant interval through the viscous sealing piece.

In the sealing method of an electric wire connected portion of thepresent invention, a press mold is usually used for pressing. When theform of the conductor connected portion is complicated, for example, inthe case of a branched wire connected portion, it is preferred thatsmall projections 51, . . . are dispersedly formed on at least one pressmold 5 as shown in FIG. 7 or convex stripes 51, . . . (having usually aheight of from 0.2 to 7.0 mm) are formed thereon as shown in FIG. 8, andthe projections or the convex stripes intruded into the film toaccelerate entering of the viscous sealing piece into gaps in theelectric wire connected portion and the inner corner thereof.

Also, when the outer diameter of a conductor connecting metal fittingsis larger than the outer diameter of an electric wire, it is effectiveto form a groove (having usually a plane area of at least 5×20 mm² and adepth of at least 0.2 mm) for partially receiving the metal fittings onthe press plate capable of pressing end portion of the electric wire.

FIG. 9 shows an example of sealing an electric wire connected portioncomprising a main electric wire 61 and branched electric wires 62 usingthe sealing material for electric wire connection of the presentinvention having a mark (not shown).

In this example, the sealing material for an electric wire connectedportion having a concaved groove 31 shown in FIG. 4 is used, an electricwire connected portion is applied to the groove 31 to perform positionmatching, the sealing material is doubled with the viscous sealing piecebeing inside using the groove 31 as a standard line to superpose theviscous sealing piece with each other, and the covered material ispressed by a press mold in the thickness direction with the end portionsof the sheet-form base material 1 in open state to complete sealing.According to the method, since the doubled viscous sealing piece ispressed with the end portions of the sheet-form base material in an openstate, the movement of the sealing material is not restricted so much,whereby a sufficient adhered area is obtained between the surface of theelectric wires and the sealing material at a low pressing pressure, thesealing material does not extrude from the end of the sheet-form basematerial, and a good electric wire connected portion is obtained.

As described above, according to the sealing material for an electricwire connected portion of the present invention, the sealing materialcan be continuously supplied and thus the sealing work can becontinuously carried out and can be easily applied to an automationline.

Also, by covering an electric wire connected portion by doubling thesealing material having the viscous sealing piece formed on one surfaceof the sheet-form base material leaving the peripheral portions, andpressing the covered material with the ends of the base material in openstate, protrusion of the sealing material at pressing can be preventedand a desired sealing effect is obtained by a low pressing pressure.

Furthermore, according to the production method of the sealing materialof the present invention, the sealing material can be continuouslyproduced and thus the product having uniform quality can be obtained ata low cost.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A sealing method for an electric wire connection,which comprisesproviding a tape-form releasable material having sealingmaterial formed thereon at a constant interval, removing a sealingmaterial for an electric wire connected portion from the tape-formreleasable material, covering an electric wire connected portioncomprising a main electric wire and branched electric wires with thesealing material for an electric wire connection portion, said sealingmaterial for an electric wire connected portion comprising a sheet-formbase material and a viscous sealing piece comprising a waterproofingcompound formed on the sheet-form base material wherein the marginalportions of the base material extended Outwardly from the marginalportion of the viscous sealing piece and the viscous sealing piece ispositioned to contact the electric wire connected portion, and pressingthe sealing material to adhere the viscous sealing piece to the surfacesof the electric wires.
 2. The sealing method of claim 1, wherein a pressmold having a plurality of small projections or convex portions on thepress surface thereof is used as the pressing means.
 3. A sealing methodfor electric wire connection, which comprisesproviding a tape-formreleasable material having sealing material formed thereon at a constantinterval, removing a sealing material for an electric wire connectionfrom the tape-form releasable material, covering an electric wireconnected portion comprising a main electric wire and branched electricwires with the sealing material for electric wire connection,saidsealing material for electric wire connection comprising a sheet-formbase material and a viscous sealing piece comprising a waterproofingcompound formed on the surface of the sheet-form base material whereinthe marginal portions of the base material extend outwardly from themarginal portion of the viscous sealing piece, said sealing materialhaving a mark for folding formed at almost center of the viscous sealingpiece by folding the sealing material using the mark as a standard withthe viscous sealing piece positioned to contact the electric wireconnected portion, and pressing the sealing material to adhere theviscous sealing piece to the surface of each electric wire.
 4. Thesealing method of claim 3, wherein a press mold having a plurality ofsmall projections or convex portions on the press surface thereof isused as the pressing means.